Document revision date: 15 July 2002

You can restrict and expand the amount of time a job is allowed in the CPU by setting CPU limit values.

Do not set CPU time limit values too low. When a job's CPU time limit is exceeded, the job is terminated with an error status. If working set values (explained in Section 14.6.4.3) are set too low, the system might use memory less efficiently but the jobs can still complete normally. However, if CPU time limit values are set too low, the system might terminate jobs that are making legitimate and authorized use of the CPU.

For example, you might use a CPU time limit on a batch queue devoted to execution of newly coded software that could unexpectedly enter a CPU loop. The CPU time limit would terminate infinitely looping jobs so they do not waste the CPU resource. However, you must be careful to choose a sufficiently high time limit so normally executing jobs do not terminate prematurely.

Another way to control allocation of the CPU resource is to create a special-purpose batch queue that shifts execution of its jobs to a less busy time of day when CPU time is more available.

14.6.4.5 Swapping

Typically, swapping is enabled on batch queues. However, for a special-purpose, high-priority queue, you might disable swapping. This provides a favorable status to jobs in this queue by removing them from consideration when memory must be reclaimed from processes (through the operating system's swapping and trimming mechanism).

For more information, refer to the OpenVMS Performance Management.

14.6.4.6 Options for Memory-Constrained Systems

On memory-constrained systems, total the pages required for the batch working sets on all batch queues. Also make sure that enough fluid memory remains for interactive jobs.

Fluid memory can be reassigned from one process to another through swapping and paging. (You can calculate fluid memory as the space that remains when you subtract the number of pages permanently allocated to the operating system from the total memory. To obtain these values, enter SHOW MEMORY.)

14.6.4.7 Optimizing Batch Queues for the Sort/Merge Utility

You can improve the efficiency of the OpenVMS Sort/Merge utility (SORT/MERGE) by designating one batch queue for sorting jobs and giving this queue a very large working set quota.

You can also set process quotas for greatest SORT efficiency. The values recommended here are based solely on SORT considerations; you should integrate other system considerations with these to determine appropriate values.

• Working set extent per process (WSEXTENT system parameter)
  For maximum sorting efficiency, use the /WSEXTENT qualifier with INITIALIZE/QUEUE, START/QUEUE, or SET QUEUE to set this value on the queue to the largest value any sorting job would ever need. Generally, the smaller the working set, the slower the sort.
  If you want to sort large files in batch mode, you need to set the WSEXTENT system parameter to a large value to accommodate the sort.
• Virtual page count per process (VIRTUALPAGECNT system parameter)
  For maximum sorting efficiency, set this system parameter to at least 1000 pages (on VAX systems) or pagelets (on Alpha systems) more than the maximum working set extent. Although SORT limits the size of the sort data structure to the process's working set extent, if work files are required, SORT can use the extra memory for I/O buffers. If this parameter is too low relative to the working set extent, SORT might be unable to create buffers for the work files when the files cannot be sorted in memory.

System managers can assign batch queues to specific resource affinity domains (RADs) in a NUMA environment. (See the OpenVMS Alpha Partitioning and Galaxy Guide for more information about RADs.)

The RAD value is a positive integer between 0 and SYI$_RAD_MAX_RADS. The SHOW/QUEUE/FULL command displays the RAD in its output.

This section describes a sequence of the commands and their effects on a batch queue. A SHOW command is included in each example to illustrate the batch queue modifications.

• The following INITIALIZE/QUEUE command creates or reinitializes the batch queue BATCHQ1 to run on node QUEBID. All jobs assigned to this queue will run on RAD 0.

  $ INITIALIZE/QUEUE/ON=QUEBID::/BATCH/RAD=0 BATCHQ1 $ SHOW QUEUE/FULL BATCHQ1 Batch queue BATCHQ1, stopped, QUEBID:: /BASE_PRIORITY=4 /JOB_LIMIT=1 /OWNER=[SYSTEM] /PROTECTION=(S:M,O:D,G:R,W:S) /RAD=0

• The following START/QUEUE command modifies BATCHQ1 to run all assigned jobs on RAD 1 of QUEBID, and readies the queue to accept jobs for processing:

  $ START/QUEUE/RAD=1 BATCHQ1 $ SHOW QUEUE/FULL BATCHQ1 Batch queue BATCHQ1, idle, on QUEBID:: /BASE_PRIORITY=4 /JOB_LIMIT=3 /OWNER=[SYSTEM] /PROTECTION=(S:M,O:D,G:R,W:S) /RAD=1

• The following SET/QUEUE command modifies the batch queue to run all assigned jobs on RAD 0 of QUEBID. Any new jobs assigned to the queue will run on RAD 0. Jobs already executing on the queue will continue to completion executing on the previous RAD value.

  $ SET/QUEUE/RAD=0 BATCHQ1 $ SHOW QUEUE/FULL BATCHQ1 Batch queue BATCHQ1, idle, on QUEBID:: /BASE_PRIORITY=4 /JOB_LIMIT=3 /OWNER=[SYSTEM] /PROTECTION=(S:M,O:D,G:R,W:S) /RAD=0

• To erase the RAD value for a batch queue, use the SET/QUEUE/NORAD command:

  $ SET/QUEUE/NORAD BATCHQ1 $ SHOW QUEUE/FULL BATCHQ1 Batch queue BATCHQ1, idle, on QUEBID:: /BASE_PRIORITY=4 /JOB_LIMIT=3 /OWNER=[SYSTEM] /PROTECTION=(S:M,O:D,G:R,W:S)

When you change the RAD value on a batch queue, the jobs currently in the batch queue are not dynamically updated with the new RAD value specified on the queue. Any executing jobs complete processing using the original RAD value. Jobs in the pending, holding, or timed execution states retain the old RAD value on the job; however, when such a job becomes executable, the job is updated with the new RAD value and runs on the RAD specified on the queue.

14.6.5 Specifying Job Scheduling Options

The queue manager uses the following criteria to determine the scheduling order for batch and print jobs that are eligible for processing:

1. Job scheduling priority
   The queue manager checks the job's scheduling priority. The job with the highest scheduling priority value is processed first. The job scheduling priority is different than the base process priority or current process priority. The user can specify job scheduling priority with the /PRIORITY qualifier of the PRINT or SUBMIT command.
2. Size (optional, and applies only to output jobs)
   By default, the job size of an output job is checked. Among jobs of identical scheduling priority, the smallest job is processed first.
   The job size is not checked if the queue has been created, started, or modified to use the /SCHEDULE=NOSIZE option.
3. Submission time
   If the jobs' scheduling priorities are identical, the job that was submitted first is processed first.

How to Perform This Task

To specify job scheduling options, follow these steps:

1. Decide if you want the order of print jobs to be based on size.
2. Decide if you want to set a block limit on jobs to be printed.

Commands for Job Scheduling Options

Use the following commands to specify job scheduling options:

Command	Description
INITIALIZE/QUEUE/SCHEDULE=[NO]SIZE START/QUEUE/SCHEDULE=[NO]SIZE SET QUEUE/SCHEDULE=[NO]SIZE	Specifies whether pending jobs in an output execution queue are scheduled for printing based on the size of the job. (Shorter jobs print before longer ones.)
INITIALIZE/QUEUE/[NO]BLOCK_LIMIT=([lowlim,]uplim) START/QUEUE/[NO]BLOCK_LIMIT=([lowlim,]uplim) SET QUEUE/[NO]BLOCK_LIMIT=([lowlim,]uplim)	Limits the size of print jobs that can be processed on an output execution queue.
PRINT/PRIORITY=n SUBMIT/PRIORITY=n SET ENTRY/PRIORITY=n	Specifies the job scheduling priority of the print job. The value of n can be from 0 through 255, where 0 is the lowest priority and 255 is the highest.

14.6.5.1 Setting Job Scheduling Priorities and Limits

The sections explain how to set job printing priorities and sizes.

How to Prioritize Jobs by Size

To prioritize jobs based on their sizes, use the /SCHEDULE=SIZE qualifier with INITIALIZE/QUEUE, START/QUEUE, or SET QUEUE. (The /SCHEDULE=NOSIZE qualifier prints jobs in the order they were submitted, regardless of size.)

In the following example, /SCHEDULE=SIZE (the default), causes short jobs to print before longer ones on the print queue LPA0_PRINT:

$ INITIALIZE/QUEUE/SCHEDULE=SIZE LPA0_PRINT

If you enter this command while pending jobs are in any queue, its effect on future jobs is unpredictable.

How to Limit the Size of Jobs

To limit the size of print jobs, use the /BLOCK_LIMIT qualifier with INITIALIZE/QUEUE, START/QUEUE, or SET QUEUE. By default, printer and terminal queues are created with no block limit, so jobs of any size will be printed. You can specify only an upper limit or both upper and lower limits.

In the following example, LPB0_PRINT has a block size limit of 50, indicating that this queue is reserved for jobs smaller than 51 blocks.

$ INITIALIZE/QUEUE/BLOCK_LIMIT=50 LPB0_PRINT

You might also want to limit the size of jobs during certain hours of the day. You can submit a batch job that runs a command procedure to set a maximum block limit of 500 blocks for a queue at 8:00 a.m. The command procedure might resubmit itself and remove the block limit after 5:00 p.m. each day. This lets users print jobs of any size after normal work hours, when the printing work load is lighter. Users can specify the /AFTER qualifier with the PRINT command to specify that a job is to be printed after a specific time.

14.6.5.2 Changing the Scheduling Priority of a Job

If a batch or print job cannot be processed, it is placed in a pending state and is not processed until the cause of the pending state is resolved. For more information, see Section 14.8.2.

To change the scheduling priority of a job, use the /PRIORITY qualifier with SET ENTRY in the following format:

SET ENTRY/PRIORITY=n entry-number

The following example changes the scheduling priority of a job to 50:

$ SET ENTRY/PRIORITY=50 1131

Do not confuse the job scheduling priority with the base process priority on a queue. The job scheduling priority value must be in a range of 0 through 255, where 0 is the lowest priority and 255 is the highest. The default value for /PRIORITY, which refers to the job scheduling priority, is the value of the system parameter DEFQUEPRI (usually set at 100).

14.6.6 Using Banner Pages

Banner pages are specially formatted pages that you can set up for queues, to help identify and separate output jobs when they exit a printer. Banner pages also help identify and separate files within jobs.

Two types of banner pages are:

• Job pages are banner pages that identify and separate jobs.
• File pages are banner pages that identify and separate files within a job.

Most sites use only a subset of the available banner pages at any given time. The following table describes the types of banner pages you can use:

Type	Description	For More Information
Job Pages
Flag page	A single page printed before each job.	Figure 14-11
Burst page	Two flag pages, divided by a separation (burst) bar, printed before each job.	Figure 14-11
Trailer page	A page printed after each job.	Figure 14-13
File Pages
Flag page	A single page printed before each file in a job.	Figure 14-12
Burst page	Two flag pages, divided by a separation (burst) bar, printed before each file in a job.	Figure 14-12
Trailer page	A page printed after each file in a job.	Figure 14-13

Table 14-2 describes the information found on job flag pages, file flag pages, job trailer pages, and file trailer pages.

Table 14-2 Contents of Job and File Pages

Item	Description
Header bar	A segmented bar composed of: For a job flag page: A single-segment bar composed of: Rows of a repeated numeral indicating the sequence of the job in the queue. An embedded text string specified by defining the PSM$ANNOUNCE system logical name. The length of the string is limited to one form width. If PSM$ANNOUNCE is not defined, the default text string is "Compaq Computer Corporation" followed by the system version number. (Use "Compaq" for shorter form width.) For a file flag page: A three-segment bar composed of: A central segment identical to the job flag page. Flanking segments with rows of a repeated character indicating the sequence of the file in the job. For a job trailer page: A three-segment bar composed of: A central segment with "END OF JOB" banner. Flanking segments with job sequence numeral. For a file trailer page: A five-segment bar composed of the following elements: Central segment with "END OF FILE" banner. Inner flanking segments with job sequence numeral. Outer flanking segments with file sequence character.
Note	A user-specified string of up to 255 characters using the PRINT/NOTE command.
Identification banner	Includes the user name of the process submitting the job, the job name, and the job number.
Qualifier phrase (file trailer page only)	Indicates the print, queue, and form qualifiers active when the job was submitted; nonactive qualifiers (except /NORECORD_BLOCKING and /NOFEED) are not included.
File sentence (file flag and file trailer pages only)	Indicates the following information: Full file specification, including device and directory, file name, type, version, and revision date and time File size in blocks File organization File owner's UIC File record characteristics: record type, carriage control, and size of longest record
Receipt box (job trailer page only)	Contains the following signoff fields: Received:, Date:, and Operator:.
Job sentence	Indicates the following information: Job name and number Name of queue to which job was submitted Submission date and time Process user name, UIC, and account Job scheduling priority Print device name Job start time Execution queue name
Footer bar	A segmented bar composed of: For a job flag page: Identical to the job flag header bar except the definition of the system logical name (PSM$ANNOUNCE) is not used as the embedded string. The default text is always used as the embedded string. For a file flag page: Identical to the file flag header bar except that the embedded text string is "Compaq Computer Corporation" followed by the operating system version number. For a job trailer page: Identical to the job flag header bar except the definition of the system logical name (PSM$ANNOUNCE) is not used as the embedded string. For a file trailer page: Identical to the file flag header bar except that the embedded text string is "Compaq Computer Corporation" followed by the operating system version number.
Ruler (file trailer and job trailer pages only)	A sequence of numbers counting to the end of the form.

Figure 14-11 shows job flag and burst pages. Figure 14-12 shows file flag and burst pages. Figure 14-13 shows file trailer and job trailer pages.

Figure 14-11 Job Flag and Burst Pages

Figure 14-12 File Flag and Burst Pages

Figure 14-13 File and Job Trailer Pages

Widths greater than 40 characters and less than 200 characters and lengths of any size greater than 40 characters are supported for file and job banner pages. Pages requested for widths greater than 200 characters are formatted and printed at 200-character widths. Lengths less than 40 characters are extended by that form length until the 40-character threshold is exceeded. Margins are not taken into account when formatting banner pages.

Commands for Specifying Banner Pages

Use the following commands when working with banner pages:

Command	Description
INITIALIZE/QUEUE/SEPARATE= option START/QUEUE/SEPARATE= option SET QUEUE/SEPARATE= option	Specifies one or more of the following job banner page options: [NO]BURST [NO]FLAG [NO]TRAILER Users cannot override the job banner pages you specify for a queue.
INITIALIZE/QUEUE/DEFAULT= option= keyword START/QUEUE/DEFAULT= option= keyword SET QUEUE/DEFAULT= option=keyword	Specifies one or more of the following file banner page options: [NO]BURST [NO]FLAG [NO]TRAILER Keyword can be either ALL or ONE. Users can override the file banner page settings you specify for a queue by specifying the /BURST, /FLAG, and /TRAILER qualifiers with the PRINT command.
PRINT/BURST[= keyword]	Specifies the ALL or ONE keyword to override, for the job, the file burst pages specified for the queue.
PRINT/FLAG[= keyword]	Specifies the ALL or ONE keyword to override, for the job, the file flag pages specified for the queue.
PRINT/TRAILER[= keyword]	Specifies the ALL or ONE keyword to override, for the job, the file trailer pages specified for the queue.

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